Windows by the numbers: September 2017

If Windows 7 were an actor, it would be a past-prime stage star who overstayed his curtain call and refused to acknowledge his understudy who, just the night before, had wowed the critics and charmed the audience.

Last month, though, Windows 7 ceded a tiny pool of the limelight to that understudy, Windows 10, giving the crowd hope that the aging actor would finally figure out he should exit, stage left, before the theater's manager got the hook and dragged him off the boards.

According to metrics vendor Net Applications, Windows 7's user share in September was 48.4%, a decline of 1.2 percentage points. More importantly, the operating system ran 52.1% of all Windows machines during the same stretch, a month-over-month drop of 1.3 points. (The second percentage is larger because Windows was detected on 90.6% of the world's PCs, not 100%; the remainder ran macOS or some kind of Linux.) This was the largest decline of Windows 7's user share — an estimate of the percentage of the world's personal computers powered by the OS — since July 2016.

Encouraging? Yes, if only because Microsoft has set Windows 7's retirement for January 2020, a date that is quickly approaching. The slower Windows 7 declines in user share, the greater the chance that panicked businesses will overspend to replace the operating system with Windows 10, causing a repeat of the chaotic end times of Windows XP.

Even with September's share erosion, Windows 7 remained behind the pace set by XP six years ago. But it did close some of the gap. At the same interval before its April 2014 retirement, with 27 months left to go, XP accounted for 51.3% of all Windows PCs, less than a point lower than Windows 7's share. The month prior, Windows 7 had been three points behind XP's tempo.

Other sources put Windows 7 in a similar spot. Irish metrics company StatCounter said that Windows 7 powered 44% of all Windows personal computers last month, a 1.1 percentage point dip from the month prior. Meanwhile, the Digital Analytics Program (DAP) also portrayed a downturn for Windows 7. DAP, which tallies visits to more than 4,000 websites maintained by U.S. government agencies, put Windows 7's September share of all Windows at 48.1%, off over two percentage points from August's 50.8%.

Windows 10 added 1.1 percentage points of user share in September — three times the increase of the month before — to account for 29.1% of all PCs and 32.1% of all Windows desktops and laptops. By Computerworld's latest calculation — using the 12-month trends as shown by Net Applications — Windows 10 will be on a third of all Windows PCs by the end of October.

Net Applications, StatCounter and DAP estimate share by detecting the agent strings of the browsers used to visit websites, then counting up the various operating systems listed in those strings.

IDG / Net Applications

Windows 7 dropped some user share in September 2017, but kept a slim majority of the Windows installed base last month, while Windows 10 edged close to a third of the installed base. (Data: Net Applications.)